Part III. Further Efficiency Improvement Analyses: Strengthening
Worksheet 15. Facility Water Balance
3. If all of the Advanced Audit activities in this guidebook have been completed, you should be able to complete most, if not all of the table on the Facility Water Balance tab in the Further Efficiency Improvement Analysis spreadsheet.
4. Estimates of use should be made for all consumption that has not been previously measured or calculated. This could include anything from water use for washing vehicles to brewing coffee.
Water Use Gallons
per year
Boiler make-up
Cooling Tower make-up 477,000
Processes and equipment Operations
Steamcleaning
Materials transport
Domestic (restrooms, breakrooms)
Toilets 1,289,000
Urinals 332,000
Faucets 120,000
Showerhead 26,000
Other Faucets
Residential Dishwasher
Commercial-Grade Kitchen
Pre-Rinse Spray Valves
Dishwashers
Ice machines 47,000
Commercial Clothes washers
Vehicle fleet wash
Once-through cooling
Landscape Irrigation 655,000
Breakroom water use
Other (Enter water use type)
Known leaks
Total 2,946,000
*Water purchased + well pumpage 3,028,000
Unaccounted for 82,000
Post-Audit Considerations and Additional Activities
The total metered inflow from your facility water bill should equal the sum of all outflows and consumption. The difference between the inflow volume (which is typically metered) and the sum of all outflow volumes (which may consist of metered volumes and calculated estimates) constitutes your facility’s unaccounted-for water. The unaccounted-for water volumes may consist of an outflow that was not previously calculated, as well as unknown leaks or errors in some consumption estimates. A difference between total metered flow and all accounted-for water use of 10 percent or less of total volume is likely due to measurement or calculation errors and is considered acceptable. Differences greater than the expected 10 percent represent discrepancies beyond the error of most
consumption calculations and suggest a leak is present or a legitimate consumption point was overlooked or underestimated (PWB 2010).
The water balance can also show large or excessive water use volumes by your facility in areas that were not previously recognized or where underestimated. These areas may be targets for improving efficiency since a small improvement in such an area can account for a large volume of water. You can also compare your facility to typical use by industry shown in the Introduction of this guide (page 15).
Spreadsheet Guidance
After completing Worksheet 15, transfer the data to the Facility Water Balance tab of the Further Efficiency Improvement Analysis spreadsheet. The spreadsheet will calculate unaccounted for water and create a pie chart similar to that in Figure 61 illustrating water use at your facility.
Worksheet 15. Facility Water Balance
Water Use Gallons per
Month/Quarter/year
Boiler make-up
Cooling tower make-up
Processes and equipment operations
Steam cleaning
Materials transport
Domestic (restrooms, breakrooms)
Toilets
Urinals
Faucets
Showerhead
Other faucets (Non-Lavatory)
Residential dishwasher
Commercial-grade kitchen
Pre-rinse spray valves
Dishwashers
Ice machines
Commercial clothes washers
Vehicle fleet wash
Once-through cooling
Landscape irrigation
Breakroom water use
Other:
Other:
Other:
Other:
Other:
Other:
Other:
Other:
Known leaks
*Water purchased + well pumpage
*Enter Metered Volume
DETERMINE THE TRUE COST OF WATER AT A FACILITY Background and Description
For many facilities, the true cost of water can be almost twice as much as the actual water and sewer charges. For example, buildings that rely on cooling towers pay for chemical treatments needed to maintain desirable water quality in the system; water used in facility processes may need to be treated to remove chemicals before it is released to the sewer system; and buildings that use heated water have added energy expenses tied to water use (NMSE 1999, Seneviratne 2007). Figure 62 (taken from the True Cost of Water tab in the Further Efficiency Improvement Analysis spreadsheet associated with this guide) is an example of an office building’s true cost of water.
When evaluating the cost of potable and sewer water, only the incremental cost should be used (i.e., the cost per 1,000 gallons or 1 ccf). This is because efficiency improvement measures do not affect base costs or hook-up fees.
Audit Objectives
This procedure will guide you through the steps to determine the true cost of water for your facility.
Figure 62. An example of the output table on the True Cost of Water tab.
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Audit Steps
1. Fill out the parts of the Basic Facility Header Sheet (page 28) that you think will apply to this audit procedure and any others you want to conduct.
2. Examine the True Cost of Water tab in the Further Efficiency Improvement Analysis spreadsheet.
3. On the Utility Rate Data Input tab, enter cost per unit for potable and sewer water (do not include base costs).
Expense Factor Cost ($)
Potable Water $9,204
Sewer $9,989
Pretreatment chemicals (if applicable) $0
Cooling Tower Water Treatment $4,000
Other (Electricity for irrigation pump) $0
Other (Electricity for heating) $4,500
Other (User Defined) $0
Other (User Defined) $0
Total Cost of water over Expense Period $27,693
Total Cost of water (Annually) $27,693
Cost of water (Potable & Sewer alone) per 1000 gallon $6.25 True Cost of water per 1000 gallons* $7.29
*Accounts for the indirect costs in the table above, but not base charges
4. Assemble a year’s worth of bills and expenses related to water consumption from your facility’s records or accounts payable; or request this information from the facility’s corporate office. Some common examples of expenses are:
a. Pretreatment chemicals (if applicable) b. Cooling tower chemical treatment
c. Electricity to pump water from an on-site well d. Pretreatment filtration of well water
e. Electricity for heating water
5. Enter these charges into the True Cost of Water tab.
6. Examine the true cost of water for your facility and compare it to the direct cost for potable and sewer water.
Post-Audit Considerations and Additional Activities
The calculation of the true cost of water should be as detailed as your available data allows. For example, you may be able to incorporate the depreciation of pretreatment machinery or irrigation well pumps. The objective is to arrive at a cost that includes the most significant direct and indirect expenses relating to water use to more accurately calculate cost savings that could result from efficiency improvements.
The true cost of water should be used whenever you evaluate potential investments in improving water use efficiency.
Spreadsheet Guidance
Utility rate data (cost of potable and sewer water and energy) were previously entered in the Utility Rate Data Input tab in this spreadsheet. If you have not entered this information, refer to the How to Use this Guide section on page 23 for an explanation.
Within the True Cost of Water tab, identify the expense period for which the costs are reflective by selecting either “Quarter” or
“Year” from a dropdown menu. This will depend on the billing data you have available and how frequently your facility is billed for water. An annual cost analysis is optimal to account for seasonal effects on water use, but shorter periods also can be analyzed.
Once you finish adding the requested billing data to the tab, the cost for potable and sewer water usage over the expense period will be calculated and displayed in the output table (Figure 62). The resulting costs for potable and sewer water should only include charges that can be reduced as efficiency increases; no base charges are reflected in this table.
Enter the costs for all expenses related to water use, such as pretreatment chemical expenses and electricity. The final output will show the true cost per 1,000 gallons of water your facility uses versus the direct cost for potable and sewer water expenses alone.
HISTORICAL WATER USE PROFILE Background and Description
Creating a historic water use profile for your facility can highlight seasonal fluctuations in potable and sewer water use and reveal spikes or drops in consumption, as well as potential leaks. Related expenses, such as those associated with chemicals for water treatment, can be tracked in tandem with water use. This profile can provide a standard when planning future efficiency improvements or to compare initial water use to conditions after efficiency measures have been put into place.
A historical water use profile can be easy to create if you have access to your facility’s utility bills. Typically, one to three years of data are gathered and viewed graphically. The Further Efficiency Improvement Analysis spreadsheet contains a table similar to Figure 63 on the Historical Water Use tab. When this table is populated, the spreadsheet will produce a graphic representation of the facility’s water
use and some related expenses. Figure 64 and Figure 65 provide examples of the graphs resulting from an office building’s historical water use profile. In the example, the office building’s cooling tower was submetered to receive sewer credits and began experiencing a leak in November.
If your billing data is quarterly and does not show monthly usage, then divide each quarter by three to get the average water use for each month in that quarter. Do not sum the total annual use and divide by 12, because this would lose any seasonal trends.
Audit Objectives
This procedure will guide you through the steps to create a graphic representation of your facility’s water use, potentially including additional water-related expenses.
Figure 63. Example input table for an office building’s historic water use profile.
*^Date
* Potable or Well Water
Inflow
* Utility Sewer Water Outflow
Cooling tower chemical expenses ($)
Mar-09 45,000 20,000 $40
Apr-09 47,000 22,000 $44
May-09 48,000 22,000 $44
Jun-09 52,000 26,000 $52
Jul-09 58,000 28,000 $56
Aug-09 57,000 27,000 $54
Sep-09 50,000 25,000 $50
Oct-09 47,000 22,000 $50
Nov-09 99,000 50,000 $45
Dec-09 98,000 49,000 $45
Jan-10 98,000 49,000 $40
Feb-10 99,000 50,000 $40
Figure 64. Example facility water use based on an office building’s historic water use profile.
Figure 65. Example facility cooling tower chemical expenses based on an office building’s historic water use profile.
0 20,000 40,000 60,000 80,000 100,000 120,000
Gallons
Facility Water Use: Inflow and Sewer Water
Potable or Well Water Inflow Sewer Water Outflow
$0
$10
$20
$30
$40
$50
$60
Dollars
Cooling Tower Chemical Treatment Expenses
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Audit Steps
1. Fill out the parts of the Basic Facility Header Sheet (page 28) that you think will apply to this audit procedure and any others you want to conduct.
2. Assemble water and sewer utility bills from the past 1 to 3 years.
3. Assemble at least a year of expenses related to water consumption. Some examples are cooling tower chemical treatment, electricity to pump water from an on-site well, pretreatment filtration of well water, and electricity for heating water.
4. Separate the use and utility billing data on a per-month basis.
5. Examine a water bill to determine the utility billing units.
6. On the Utility Rate Data Input tab, enter cost per unit for potable and sewer water (do not include base costs).
7. Examine the Historic Water Use Profile tab on the Further Efficiency Improvement Analysis spreadsheet.
8. Enter the water use data into the Historical Water Use Data Input table (in ccfs or gallons, depending on the selected billing unit).
9. Examine the graphs produced.
Post-Audit Considerations and Additional Activities
After examining the graphs of your facility’s water use, consider any seasonal or annual variations or spikes or drops in water use that you see. If they cannot be explained by the operations of the facility, they may be areas where further investigation is needed. Once this profile has been created, subsequent water use and related expenses should be added, and notations should be made to monitor when efficiency improvements are made. In this way, the profile serves as a benchmark against which the impacts of those efforts are measured.
Spreadsheet Guidance
Utility rate data (cost of potable and sewer water and energy) are entered in the Utility Rate Data Input tab. If you have not entered this information, refer to the How to Use this Guide section on page 23 for an explanation.
To complete this audit, refer to the Historic Water Use Profile tab on the Further Efficiency Improvement Analysis spreadsheet. In the input table, enter the billing periods, inflow meter records, outflow meter records, and cooling tower chemical expenses.
IDENTIFYING ON-SITE ALTERNATIVE WATER SOURCES Background and Description
Many buildings have the opportunity to develop and use alternative on-site water sources, and numerous case studies document significant water and financial savings (NMSE 1999). However, evaluating the feasibility of developing alternative water sources can only be done on a case-by-case basis.
Considerations during such an evaluation include relevant health and safety requirements; the volume, quality, and reliability of the source; possible pretreatment requirements; and suitability for possible uses within the facility. Guidance for a feasibility analysis of any system at a specific facility is beyond the scope of this guidebook.
If your facility is considering such an analysis, consider contacting a conservation or engineering consulting firm.
Possible sources of on-site alternative water include the following:
Harvested rainwater
Water from once-through cooling equipment
Boiler condensate
Condensate from air handling units
Fountain drain water
Cooling tower blowdown
On-site treated gray water and wastewater
Internally recycled water (last rinse water becomes next load’s wash water)
These alternative on-site water sources produce water at a range of qualities creating various opportunities for use. Potential uses include:
Cooling tower makeup
Boiler makeup
Landscape irrigation
Sanitation (toilet and urinal flushing)
Makeup water for ornamental ponds or fountains
Swimming pools
Laundry water
Manufacturing processes
Materials transport
Due to the complexity of this topic, this section is primarily intended as educational. Estimates of potential water created by only two of these sources, condensate from the cooling system and rain from the facility’s roof, will be determined on the On-Site Alternative Water Sources tab of the Further Efficiency Improvement Analysis spreadsheet.
The Cooling Tower Water Use – Advanced Audit (page 139) includes a calculator to estimate condensate from cooling system air handling units. A similar, though abridged, calculator has been included on the On-Site Alternative Water Sources tab of the Further Efficiency Improvement Analysis spreadsheet. Cooling tower air handling units can produce significant volumes of water that can be used to offset cooling tower makeup needs. Moreover, this source is extremely low in total dissolved solids, thus requiring little pretreatment for solids, but may require some biological control.
The second alternative water source estimation procedure involves calculating potentially harvested rain water. Harvested rain water can be used for many nonpotable purposes, such as vehicle washing, supplementing irrigation water, providing makeup water for fountains, and for use in some manufacturing processes not requiring high quality water. Each 1,000 square feet of a building’s roof area can collect approximately 500 gallons of water from 1 inch of rain.
Storage containers for harvested rainwater
Audit Objectives
You will:
Become more acquainted with the concept of utilizing on-site alternative water sources
Estimate the volume of water that could be collected at your facility via two sources (the cooling system’s air handling unit and rainwater harvested from the facility’s roof)
Audit Steps
Before beginning, you may want to review the Alternate On-Site Water Sources section of the WaterSmart Guidebook (EBMUD 2008)1.
1. Fill out the parts of the Basic Facility Header Sheet (page 28) that you think will apply to this audit procedure and any others you want to conduct.
2. Examine the On-Site Alternative Water Sources tab on the Further Efficiency Improvement Analysis spreadsheet.
3. Enter the number of cooling tons of the facility’s cooling tower, the hours per day it operates, and the days per month it operates into the first input table.
4. Examine the output.
5. Enter the building’s roof area in square feet into the second input table.
6. Examine the output in conjunction with the average rainfall for your location (See Table 19 for average rainfall data for some locations in Florida).
1 Available through www.allianceforwaterefficiency.org/WaterSmart_Guidebook_for_Businesses.aspx or go to www.allianceforwaterefficiency.org and enter, “WaterSmart Guidebook” into the search bar.
Post-Audit Considerations and Additional Activities
Table 19 provides an example of the rainwater harvesting potential for facilities in Florida.
Similar information should be available for most areas.
If you feel there is potential to capitalize on any of the potential on-site water sources at the facility, contact a professional engineering firm to discuss site-specific considerations and costs associated with the capture, storage, and use of the alternative water.
Spreadsheet Guidance
Utility rate data (cost of potable and sewer water and energy) should have been previously entered in the Utility Rate Data Input tab. If you have not entered this information, refer to the How to Use this Guide section on page 23 for an explanation.
For this audit, refer to the On-Site Alternative Water Sources tab on the Further Efficiency Improvement Analysis spreadsheet. There are two input/output tables on this tab. The first pertains to the amount of condensate water potentially created by the cooling system’s air handling unit that can be used to supplement
cooling tower make-up. Enter the number of typical cooling tons of your facility’s cooling tower and the number of hours per day and days per month it operates. The output consists of potential savings in gallons and dollars.
The second input/output table pertains to potential gallons of rainwater than can be harvested from your facility’s roof during a 1 inch rain event and annually. Enter the building’s roof area in square feet and the number of inches of rain received in the city closest to your own (for Florida locations, check Table 19; information for other areas can be found by searching online). An abridged version of this table, titled Local Rainfall Averages, has been provided on the On-Site Alternative Water Sources tab of the spreadsheet for this purpose. The potential gallons captured and the subsequent savings shown are absolute potentials. The actual savings available to your facility depends on the size of the storage tank and how rapidly the water is used and may be less than the absolute potential amount. However, if the absolute amount appears to be substantial, you may want to contact a professional engineering firm to discuss site-specific considerations and costs associated with rainwater capture, storage, and use.
Florida Focus
Table 19. Average monthly rainfall for selected Florida locations.
Location J F M A M J J A S O N D Annual
Arcadia 2.2 2.6 2.7 2.1 4.3 7.8 8.3 7.3 7.4 4.0 2.0 2.2 52.9 Daytona Bch. 2.4 3.1 3.0 2.3 3.4 6.4 5.5 6.3 6.7 4.6 2.6 2.2 48.5 Fort Myers 1.9 2.1 2.9 1.5 4.1 8.7 8.6 8.6 8.6 3.9 1.4 1.6 53.9 Gainesville 3.3 3.9 3.7 3.0 4.2 6.6 7.1 8.0 5.6 2.3 2.0 3.2 52.8 Jacksonville 3.1 3.5 3.7 3.3 4.9 5.4 6.5 7.2 7.3 3.4 2.0 2.6 52.8 Key West 1.7 1.9 1.3 1.5 3.2 5.0 3.7 4.8 6.5 4.8 3.2 1.7 39.4 Lake City 3.8 3.9 4.2 3.5 4.6 6.7 6.8 7.0 5.7 2.4 2.3 3.5 54.4 Lakeland 2.3 2.8 3.5 2.4 4.2 6.1 7.3 7.5 5.8 2.4 1.9 1.9 48.3 Miami 2.1 2.1 1.9 3.1 6.5 9.2 6.0 7.0 8.1 7.1 5.7 7.9 57.6 Pensacola 5.1 5.0 6.1 4.8 4.3 7.1 7.2 6.4 6.8 3.4 3.9 5.4 65.5 Tallahassee 4.5 4.6 4.6 4.4 4.4 5.5 6.9 5.5 5.9 2.7 2.8 4.1 55.8 Tampa 2.6 3.5 3.9 2.2 4.7 7.0 7.9 8.4 7.1 3.1 2.2 2.7 55.3
Source: University of Florida, Institute of Food and Agricultural Sciences.
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Related Resources
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References Cited
AWE. 2010. Ice Machines Introduction. Alliance for Water Efficiency.
http://www.allianceforwaterefficiency.org/Ice_Machines.aspx.
AWUWCD. 2006. Water Efficient Equipment and Design, A Guide for Non-Residential Construction and Development. Austin Water Utility Water Conservation Division, Austin, TX.
http://www.austintexas.gov/department/water-conservation.
AWWA. 1999. Testing of Meters – Testing Procedures and Equipment. Guidebook M6, Meter Selection, Installation Testing and Maintenance. American Water Works Association, Denver, CO.
Building Green. 2010. Alternative Water Sources: Supply-Side Solutions for Green Buildings. Building Green, LLC. Uwww.buildinggreen.comU.
California Urban Water Conservation Council. 2009. How to Read Your Water Meter. California Urban Water Conservation Council, Sacramento, CA. Uwww.h2ouse.net/resources/meter/index.cfmU.
Cardenas-Lailhacar. B., M. D. Dukes, and G.L. Miller. 2010. Sensor-Based Automation of Irrigation on Bermuda Grass During Dry Weather Conditions, J. Irrigation and Drainage Eng 136(3):161-223.
Colorado WaterWise Council. 2007. Benchmarking Task Force Collaboration for Industrial, Commercial &
Institutional Water Conservation, Colorado WaterWise
Council. Uhttp://coloradowaterwise.org/Resources/Documents/ICI_toolkit/docs/Brendle%20Group%20and%2
Council. Uhttp://coloradowaterwise.org/Resources/Documents/ICI_toolkit/docs/Brendle%20Group%20and%2